This invention relates to an automatic performance device used in a keyboard instrument such as piano, organ, cembalo and celesta.
Known in the art of an automatic performance device for a keyboard instrument is one which, for example, is shown in FIG. 9.
An upright piano 1 shown in the figure has a key bed 2, a balance rail 3 provided on the upper surface of the key bed 2 at about a middle position as viewed in the figure, a key 5 which is rockably supported on the balance rail 3 through a balance pin 4, a rear rail 6 provided on the key bed 2 in the rear end portion thereof, a stop 7 made of an elastic material against which the rear lower surface of the key 5 abuts, a front rail 8 provided on the upper surface of the key bed 2 in the front end portion thereof, an oval key pin 9 which is fixed to the front rail 8 and engages with the front lower surface of the key 5 to restrict the movement of the key 5 in a direction normal to the rocking direction thereof, a string 10 provided in correspondence to the key 5 and a string striking mechanism 11 provided between the string 10 and the key 5. This string striking mechanism 11 includes a hammer 12 for striking the string 10, a damper 13 for stopping vibration of the string 10 and an action 14 which connects the hammer 12 and the damper 13 with the key 5.
An automatic performance device 15 applied to the piano 1 of the above described construction includes a solenoid 16 provided on the upper surface of the key bed 2 at a location between the rear rail 6 and the balance rail 3 and a controller 17 for actuating the solenoid 16.
The operation of this prior art automatic performance device 15 will be described below.
A key actuating signal is provided from the controller 17 to the solenoid 16 in response to a performance signal from an external input 18 and the key 5 is moved in a rocking motion with a force corresponding to the key actuating signal.
As the key 5 is moved, the damper 13 is released from the string 10 and the hammer is actuated to strike the string 10 respectively through the action 14.
Since the string striking force applied to the hammer 14 corresponds to the force applied to the key 5, the string striking force corresponding to the performance signal supplied from the external input 18 can be provided.
The prior art automatic performance device described above has the problem that, since the operation of the solenoid 16 which is actuated in response to the performance signal to move the key 5 is independent from the rocking motion of the key 5, there sometimes arises an error between the movement of the key 5 which is predetermined by the performance signal and the reproduced real movement of the key 5 for one reason or another, e.g., inertia of the key 5 during the rocking motion, so that fidelity of the reproduced performance is impaired due to this error which results in an error in tone generation timing, omission of a weak sound or the like.
It is, therefore, an object of the invention to provide an automatic performance device for a keyboard instrument which has overcome the above described problem.